Field of the Invention
The present subject matter relates to weep screeds that facilitate the application of veneer building materials such as stucco, stone, and brick on external walls.
Related Art
In one form of construction, stucco veneer, brick veneer, stone veneer and other such external veneer building materials are used as an exterior finished wall material for residential and commercial buildings. These materials allow architects to provide a variety of different low maintenance designs and wall textures.
A weep screed is a building device used with veneer building finishes. It is used where the veneer material terminates. In one application, the weep screed is attached along the base of the exterior wall where the wall meets the top of the building foundation, e.g., the weep screed is placed strategically to overlap the joint between the exterior framed wall and the foundation. This prevents water, e.g., rain and sprinkler water, from entering between the external wall and the foundation. Such devices are also used to support the end of the veneer structure and to provide a means for moisture to escape from behind the veneer finish.
Current methods for applying outer veneer finishes use layers of various building materials. For example, for a stucco veneer application on a plywood sheathing outer wall, a weep screed is attached overlapping the boundary between the foundation and the outer wall supported on the foundation. The plywood sheathing is then covered with a weather barrier material such as Tyvek®, which extends onto and terminates in the weep screed. Over the weather barrier is provided a drainage mat, such as Driwall™ Rainscreen, which is a permeable mat-like material that allows water to drain through it. Over the drainage mat is provided a mesh, such as a wire lath, which acts as a support frame for holding the plaster in place, and which stabilizes the first coat of wet plaster when initially applied. The first coat of wet plaster, e.g., the scratch coat, is applied onto the mesh. The second or brown coat of plaster is applied over the first coat of plaster, and the final finish or stucco coat is applied onto the second coat to finish the stucco veneer system. The various layers discussed above terminate at the weep screed.
One potential issue with such materials is the possibility of moisture and water getting behind the finished wall veneer material. For example, stucco, a plaster material, and brick and stone veneer, which use cementuous materials, are porous and may absorb water and water vapor into the building layers beneath the exterior stucco surface (the term plaster as used herein includes plaster and cementuous like materials used in such veneers). Water vapor can also condense behind the exterior veneer surface. Furthermore, poor construction techniques, particularly around windows where waterproofing may be applied improperly allow rainwater to get behind the exterior veneer wall. The water will drain down the inside of the veneer structure between the various construction layers, particularly through the drainage mat if used. If not collected and removed properly, this water can damage the finished veneer material. For example, if water within or along the veneer finish freezes, it can cause the veneer to crack and pieces to break off.
One problem with prior art weep screeds is that they do not effectively facilitate drainage of the water from behind the veneer structure. One type of weep screed, as shown in U.S. Pat. No. 5,630,297 to Rutherford, shields the boundary between the building foundation and the external wall from water, but provides little support for the veneer and little water management for water draining through a drainage mat. In some cases, a second device, e.g., a J-bead, is added in addition to the weep screed for support and water management, but this requires a second piece and added costs associated therewith.
Other types of weep screeds include a series of small holes through the flange on which the veneer layers terminate. See, e.g., U.S. Pat. No. 6,385,932 to Melchiori. The holes, however, are typically located away from the back flange of the weep screed such that they sit below the plaster layer of the veneer and not the drainage mat layer. Moreover, because of their position and size, these holes may become plugged with plaster and not drain water effectively. The water may be retained behind and or under the veneer, or flow under the lower end of the veneer towards the edge of the weep screed. All of this can cause the veneer finish to crack and break over time, particularly when the water freezes.
Accordingly, an improved weep screed and an improved means for installing such veneer building finishes would prove beneficial.